Mountain ranges rise faster than believed: studyJune 6th, 2008 - 12:06 pm ICT by IANS
Washington, June 6 (IANS) Mountains can double their heights within two to four million years - many times faster than the existing tectonic theory surmises, a new study has found. The rapid uplift implies that the current theory of plate tectonics will have to be modified to include a process of “delamination”, according to Carmala Garizone of the University of Rochester.
The Indian Institute of Science (IISc) in Bangalore collaborated in the study.
The traditional method of estimating the growth of mountains is by studying the history of the folding and faulting of the Earth’s upper crust. Under this paradigm, geologists have estimated that the Andes in South America rose gradually over the past 40 million years.
Garzione and her collaborators, including Prosenjit Ghosh of IISc, used the latest techniques to measure how ancient rainfall and surface temperature altered the chemical composition of a mountain’s soil.
By studying sedimentary basins in the high Andes, the team could determine when and at what altitude these ancient sediments were deposited.
That record of altitude changes shows that the Andes mountains rose slowly for tens of millions of years, but then suddenly lifted much faster between 10 and six million years ago.
The findings of the study have been presented in the latest edition of the journal Science.
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